Prevention of preterm birth by cervical cerclage compared with expectant management: A systematic review

Our objective was to review the evidence on the use of cervical cerclage to prevent preterm births compared with expectant management. An OVID, MEDLINE, Cochrane Database, and Science Citation Index search using the medical subject headings and terms "cervical cerclage," "cervical incompetence" and "preterm delivery" was conducted for the period 1966 to 2002. We included all randomized trials that evaluated the effectiveness of cervical cerclage in preventing preterm birth. Using a standardized data collection instrument, we reviewed trial designs, inclusion and exclusion criteria, and maternal and neonatal outcome. Fixed or random effects model were used to pool both dichotomous and continuous outcomes where appropriate. Seven trials were identified; six met our inclusion criteria. A total of 2190 women enrolled into the trials were identified with 1110 receiving cerclage and 1080 managed expectantly. There were a total of 278 of 2190 (12.7%) deliveries before 34 weeks of gestation. The meta-analysis demonstrated a trend toward cervical cerclage preventing preterm delivery at less than 34 weeks (OR 0.77, 95% Cl, 0.59, 0.99; P = .049). However, there was no demonstrable improvement in neonatal mortality (OR of 0.0.86, 95% Cl, 0.56, 1.33; P = .50). There is a trend toward cervical cerclage reducing preterm births before 34 weeks. The use of cerclage is, however, associated with an increased risk of postpartum fever.